Braking mechanism

ABSTRACT

A braking mechanism for a railway car including feeler appratus mounted on each side of a railway car body for indicating movement of the bolster with respect to the truck side frames, load compensating apparatus connected to the brake cylinder pipe for varying pressure of air in the brake cylinder, and equalizer apparatus for receiving vertical movement indications from the feeler apparatus and sending corresponding indications to the load compensating apparatus.

[451 Nov. 28, 1972 United States Patent Beacon 2,385,139 9/1945Kelley........................188/195 [54] BRAKING NIECHANISM [72]Inventor:

Robert G. Beacon, Sparta, NJ.

Primary ExaminerDuane A. Reger Attomey-Ward, McElhannon, Brooks &Fitzpatrick Totowa [73] Assignee: Ellcon-National,

Inc.,

Borough, NJ. Sept. 25, 1970 [21] Appl. No.: 75,447

[22] Filed:

feeler appratus mounted on each side of a railway car body forindicating movement of the bolster with Related Apphcahon Data respectto the truck side frames, load compensating apparatus connected to thebrake cylinder pipe for [63] Continuation-impart of Ser. No. 11,230,Feb.

varying pressure of air in the brake cylinder, and

equalizer apparatus for receiving vertical movement indications from thefeeler apparatus and sending cor- [52] US. 188/195 respondingindications to the load compensating [51] Int. Cl....... 8/22 paratus[58] Field of Search .188/195; 303/22 R, 22 A, 23 R, 303/23 A s Clains,3 Drawing Figures.

[56] References Cited UNITED STATES PATENTS 1,774,162 8/1930Whitaker.................303/23R BRAKING MECHANISM This application is acontinuation-in-part application of my copending application Ser. No.11,230, titled Braking Apparatus," filed Feb. 13, 1970.

This invention relates to brake mechanisms, and more particularly toempty and load brake mechanisms for standard railway cars.

The Association of American Railroads and the Federal RailroadAdministration specify the brake requirements for freight trains. Allfreight cars are equipped with an air brake system which must becompatible with every other car. Air pressure, under the control of theengineer, is applied to one or more brake cylinders on a freight carwhich directly, or through a lever system, applies the brake shoes tothe wheels. The friction of the brake shoes against the wheel retardsthe turning of the wheel, thereby stopping the moving vehicle. However,the retarding force against the wheels must never exceed the frictionforce or adhesion between the wheel and the rail or the wheel willslide. Sliding results in a longer stopping distance and damage to thewheels and, hence, must be avoided. The maximum brake shoe forcepermissible is a function of the weight of the wheel on the rail. Thisweight differs substantially from when the railway car is empty to whenthe railway car is loaded and, generally, there is no provision on thecar to change the brake shoe force to compensate for this change inweight. If the desired brake shoe force is applied for a loaded car thenthis force will cause sliding of the wheels when the car is empty. Thus,the empty car weight governs the maximum brake shoe force that can beapplied. From experience this maximum force, expressed as a percentageof the weight of the car, is about 75 percent of the empty car weight.However, to meet minimum stopping requirements, this retarding forcemust also not be less than 18 percent of the maximum weight of theloaded car. These percentages are for cars equipped with cast iron brakeshoes. When composition brake shoes are used, and they are becomingincreasingly popular, the percentages are different because thecoefficient of friction of the composition shoe is higher than that ofthe cast iron shoe, but the same problem exists.

The weight of the car when it is empty determines whether or not theproper braking ratios can be obtained. That is, the force that produces75 percent of the empty weight must produce the minimum 18 percent ofthe loaded car weight. If the empty car weight is too low, compared tothe loaded car weight, then the percentage of the loaded car weight willbe under the minimum. Several arrangements have been used in thiscountry in the past to overcome this problem. According to onearrangement, compensating dead weight was added to the empty car, butthis was uneconomical. Another prior art arrangement utilized two brakecylinders. When the car was empty, air was supplied to one brakecylinder, and when the car was loaded, air was supplied to both brakecylinders, thereby increasing the brake shoe force. Still anotherarrangement employed a differential piston whereby air was applied toboth sides of the piston when the car was in its empty condition, andwhen it was in its loaded condition, air was applied only to one side ofthe piston.

In the last two arrangements described above, the deflection of the carsprings was used as a measure of the load being carried by the car. Somesort of measuring device was employed to indicate that the car springswere either extended for the empty car weight or compressed for theloaded car weight, and at some midposition between empty and loaded, theindicator would switch the brake from the empty mode to the loaded mode.The prior art methods were expensive to buy and costly to maintain.Related patents in this art include US. Pat. No. 1,230,949 issued June26, 1917; US. Pat. No. 2,395,170 issued Feb. 19, 1946; US. Pat. No.2,408,123 issued Sept. 24, 1946; US. Pat. No. 3,335,825 issued Aug. 15,1967; and US. Pat. No. 3,338,640 issued Aug. 29, 1967.

The present invention involves a novel combination of features combinedin such a way as to afford a very efficient solution to the difficultiesencountered with the prior art, as will be apparent as the descriptionpipe connecting the brake control valve to the brake cylinder. Feelermeans are mounted adjacent each side of the truck for indicatingvertical travel of the bolster with respect to the truck side frame. Aload compensating cylinder assembly is connected to the brake cylinderpipe. This assembly comprises a cylinder, a piston mounted in thecylinder, a T-bar having one end mounted on the piston, a pawl and rackmeans operatively connected to the T-bar and a lever drilled to apredetermined ratio. Also, there is provided equalizer means mounted inthe feeler box for receiving vertical movement indications from each ofthe feeler means and sending one corresponding indication to the pawlmeans, thereby locking the piston in a position corresponding to theload of the railway car and, hence, regulating the volume and pressurein the brake cylinder.

There has thus been outlined rather broadly the more important featuresof the invention in order that the detailed description thereof thatfollows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described more fullyhereinafter. Those skilled in the art will appreciate that theconception on which this disclosure is based, may readily be utilized asthe basis forthe designing of other structures for carrying out theseveral purposes of the invention. It is important, therefore, that thisdisclosure be regarded as including such equivalent constructions as donot depart from the spirit and scope of the invention.

One embodiment of the invention has been chosen for purposes ofillustration and description, and is shown in the accompanying drawings,forming a part of the specification, wherein:

FIG. 1 is a perspective view, partially schematic, of a brake mechanismconstructed according to the concept of this invention;

FIG. 2 is an enlarged side elevation of a load compensating cylinder,and feeler means in their brake released, car empty, positions; and

FlG. 3 is an enlarged side elevation of the load com pensating cylinder,and feeler means in their brake applied, car empty, positions;

When a train is made up at a terminal,'the locomotive pumps air througha supply reservoir 10, FIG. 1, brake valve 12 and a pipe line extendingthrough all of the cars in the train, known as the brake pipe 14. Oneach individual car, this brake pipe air enters an air brake controlvalve 16, pushes back a piston or spool valve, not shown, and fills atwo compartment reservoir to a pressure equal to the brake pipe. Oneside of this reservoir is known as an auxiliary reservoir 18 whichprovides air pressure to the braking system of this car when a normalservice application of the brakes is irequired. The other side is anemergency reservoir which provides additional volume when an emergencyapplication of the brake is initiated.

' When the engineer applies the brakes from the locomotive, he exhaustsaim-thereby reducing the pressure in the brake pipe 14 which upsets theequilibrium of a service piston, not shown, located in the control valve16 and makes a connection between the auxiliary reservoir 18 and a brakecylinder 22 via a brake cylinder pipe 23. Air will flow from theauxiliary reservoir to the brake cylinder until the auxiliary reservoirpressure equals that of the brake pipe, at which time the valve closes,thereby cutting off all connections.

In order to release the brakes, the engineer again charges the brakepipe 14, and when the pressure rises above that of the auxiliaryreservoir 18, the service piston in the control valve 16 will makeconnections, whereby the brake pipe again charges the auxiliaryreservoir 18 while the brake cylinder 22 becomes connected to exhaust.

The auxiliary reservoir air which passes to the brake cylinder 22 duringapplication of the brakes builds up a pressure on the face of the brakecylinder piston and transmits a force through an arrangement of leversand rods (not shown) to apply friction shoes to the treads of the wheels(not shown). The force of the brake shoes on the wheels increases indirect proportion to the brake cylinder pressure developed, and governsthe amount of retardation in proportion to the amount of the frictionforce developed and the weight of the car being decelerated. Thisretarding force must not exceed the adhesion of the wheel to the rail orthe wheel will skid, resulting in flat spots on the wheel tread which isobjectionable and expensive to repair.

The amount of air pressure developed in the brake cylinder is in directproportion to the amount of brake pipe air exhausted by the engineer,until equalization between the pressures in the auxiliary reservoir 18and the brake cylinder 22 occurs. Any further reduction of the brakepipe air will have no effect. An emergency application will, however,develop approximately 20 percent more brake cylinder pressure than afull service application.

The lever ratio in the brake rigging is normally designed to obtain themaximum friction force that can be used on an empty car according togoverning authorities. This force is usually inadequate for a fullyloaded car, and according to this invention means are provided toincrease this force.

As best seen in FIG. 1, railway freight cars are supported on two ormore trucks comprising two or more wheel sets 24 attached together bytruck side frames 26 and bearing arrangements. These side frames areunsprung members resting on the axle on each side of the truck. Tyingthese truck side frames together is one or more truck bolsters 28resting on bolster springs 30 contained in each truck side frame andsupporting the car body in the center.

As the weight of the railway car increases, the bolster springs 30deflect proportionately, to bring the car body 29 and truck side frames26 nearer each other on both sides of the truck. Each spring set has apreselected travel and the amount of spring travel is directlyproportional to the weight of the car and its contents, if any. Feelermeans, indicated generally at 31, are mounted on each side of the carbody in feeler boxes 31A and31B for purposes of indicating the verticaltravel of the car body with respect to the truck side frames 26. Saidfeeler means include tubes, levers and rods enclosed in boxes on eachside of the car body.

Plates 27, may be attached to the truck side frames to stop said feelermeans, or the top surface 25, of the truck side frames, may be useddirectly for this purpose. Bythis means, the weight of the car istransformed into linear movement which is used to control the amount ofthe brake force as will be pointed out more fully hereinafter.

A load compensating cylinder assembly, indicated generally at 36, istied into the existing brake cylinder pipe 23 on the railway car. Asbest seen in FIGS. 2 and 2, this assembly comprises a cylinder 38, apiston 40 mounted in said cylinder, at T-bar 42 having one end mountedon said piston and .a pawl 44 pivotally mounted on the other endthereof. The cylinder 38 has an end wall 46 and a return spring 47interposed between the end wall and the piston 40 for returning thepiston to its lefthand position, as viewed in FIGS. 2 and 3. The endwall 46 carries housing 48 for the pawl 44 and ratio lever 62. Thehousing has an opening 50 in the end adjacent the piston 40 for thepassage of the T- bar 42. Also, the housing has a lower guide assembly52 for guiding the movement of the T-bar. A rack 54 is mounted on thehousing 48 for receiving the pawl 44.

Said pawl is attached to a ratio lever 62 by a pawl bar 61. The purposeof the ratio lever 62 is to convert the relatively short feeler travelto the longer travel of the piston 40 in a direct ratio to the feelertravel. A pawl spring 56 is at one end of theratio lever 62 for urgingsaid pawl out of engagement with said rack 54.

A sheathed cable 58 is attached to theend of the ratio lever 62 forpurposes of urging the pawl into en gagement with the rack 54, as shownat 60, FIG. 3.

The other end of the cable 58 is connected to a medial portion of anequalizer bar 76 located in the primary feeler box 31A for purposes ofobtaining the average travel of feeler'tubes 32 mounted in feeler boxes31A and 3113 on each side of the railway car, respectively.

As viewed in H6. 3, in operation when the brakes are applied, the brakecylinder air enters the load compensating cylinder assembly 36 from thebrake cylinder pipe 23 and applies pressure against the face of thepiston 40. The spring 47 holds back movement of the piston until a forceequal to the compression of the spring is built up. This is necessary toinsure that every brake application, regardless of the amount of brakecylinder pressure buildup, is transmitted to the brake shoes. When thespring force is overcome, the piston 40 will move to the right, asviewed in FIG. 3, pushing the pawl 44 therewith as it is being held outof engagement with the rack 54 by means of the spring 56. The pawlpushes the bottom of the ratio lever 62 to the right, as viewed in FIG.3, and as it is pivoted at a predetermined point, pulls the sheathedcable from the primary feeler box 31A. This movement; in turn, moves theequalizing lever 76 and the feeler lever 75 and rod 77, pushing thetubes 32 in the feeler boxes 31A and 313 down until end members 79strike the truck side frames at 25, or plates 27. When the end members79 strike the plates 27, further movement of the ratio lever 62 isprevented and additional movement of the piston 40 rotates the pawl intoengagement with the rack 54 to lock the piston 40 against furthermovement. This has the result of allowing the piston 40 to travel to theright, as viewed in FIG. 3, a distance proportional to the movement ofthe feeler means 31 which corresponds to the weight of the railway car.Accordingly, a fully loaded railway car will have little volume in thecylinder 38 while an empty car will have a preselected larger volumewhich is equivalent to the full travel required for that particularseries of freight cars. The volume in the cylinder 38 in effect createsa reservoir which increases the amount of space to be filled by thevolume of air from the auxiliary reservoir 18, FIG. 1. The result is apreselected pressure in the brake cylinder 22 and a corresponding forcetransmitted to the brake shoes through the brake rigging.

When the train brakes are released, as viewed in FIG. 2, the airpressure exhausts from the front of the 'piston 40 anda return spring 47pushes the piston 40 back to its release position pulling the entiremechanism along with it. Accordingly, the movement of the feeler meanswill determine the volume in the cylinder for each brake application.

The equalizer bar 76 in the primary feeler box 31A insures that a truefeeler travel is fed to the ratio lever 62. If a car is loadedoff-center or the brake application is initiated when the car is tippedto one side as when going around a curve, one feeler will have a longtravel, while the other will have a short travel and the average ofthese two travels will be transmitted by the tipping motion of theequalizer bar, thereby providing a true reading. If a car is rockingfrom side to side as it goes down the track, this side motion will betaken up by the equalizer bar and will eliminate false readings whichmight otherwise be obtained. Each feeler tube 32 contains an overtravelspring arrangement 35 to protect the mechanism from undue force if thecar is loaded with the mechanism engaged.

It will thus be seen that the present invention does indeed provide animproved braking system which is superior in simplicity, economy andefficiency as compared to prior art such devices.

Although a particular embodiment of the invention is herein disclosedfor purposes of explanation, various modification thereof, after studyof this specification, will be apparent to those skilled in the art towhich the invention pertains.

What is claimed and desired to be secured by Letters Patent is:

feeler means mounted in a feeler box on each side of the car bodyadjacent said truck for indicating vertical travel of the bolster withrespect to said truck sideframes, a load compensating cylinder assemblyconnected to said brake cylinder pipe, said assembly comprising acylinder, a piston mounted in said cylinder, a T-bar having one endmounted on said piston, pawl and rack means operatively connected tosaid T-bar, equalizer means mounted in one of said feeler boxes forreceiving vertical movement indications from each of said feeler meansand sending a corresponding indication to said pawl means.

2. A braking mechanism according to claim I wherein each of said feelermeans comprises a feeler tube containing a stiff spring, said tubehaving an end member extending outwardly, said end member being mountedadjacent the truck side frame for movement proportional to the weight ofsaid railway car.

3. A braking mechanism according to claim 2 wherein said equalizer meanscomprises an equalizer bar mounted in one of said feeler boxes, linkagemeans connected to the outer ends of said equalizer bar to said feelertubes, means connecting the mid-portion of said equalizer bar to thepawl in the load compensating cylinder assembly.

4. A braking mechanism according to claim 1 wherein said feelermeans andsaid equalizer means comprise an equalizer bar mounted in said one ofthe feeler boxes, means operatively connecting said equalizer bar tosaid pawl and rack means, a first feeler lever connected to saidequalizer bar, a member extending outwardly of said feeler box adjacentone of the truck side frames for movement proportional to the weight ofsaid railway car, means connecting said member to said first feelerlever, a second feeler lever mounted in the other of said feeler boxes,a rod connecting said second feeler leverto said equalizer bar, a secondmember extending outwardly of said other feeler box adjacent the otherof the truck side frames for movement proportional to the weight of saidrailway car, and means conmeeting said second member to said secondfeeler lever.

5. A braking mechanism according to claim 1 wherein said loadcompensating cylinder assembly comprises a pawl pivotally mounted onsaid T-bar, said cylinder having an end wall, a return spring interposedbetween said end wall and said piston, a housing carried by said endwall, said housing having a rack mounted thereon for receiving saidpawl, a ratio lever, a pawl bar connecting said pawl to said ratiolever, a sheathed cable having one end attached to said ratio lever forurging said pawl into engagement with said rack, the other end of saidcable being attached to said equalizer means, a pawl spring connected tosaid ratio lever for urging said pawl out of engagement with said rack.

6. A braking mechanism according to claim wherein said compensatingcylinder assembly further comprises an opening in the end adjacent saidpiston for the passage of said T-bar, and lower guide means in saidhousing for guiding the movement of said T-bar.

.7. A braking mechanism according to claim 1 wherein said equalizermeans comprises an equalizer bar, and said load compensating cylinderassembly comprises ratio lever means connected to said pawl and rackmeans, cable means connecting said equalizer bar with said ratio levermeans, and said feeler means being connected to said equalizer bar.

8. A braking mechanism for a railway car having a truck including sideframes, pairs of wheels, a truck bolster resting on bolster springscontained in each truck side frame and a car body carried by said truckbolster, said mechanism comprising a brake pipe, an air brake controlvalve connected to said brake pipe, an

auxiliary reservoir connected to said control valve, an

emergency reservoir connected to said'control valve, a brake cylinder, abrake cylinder pipe connecting said air brake control valve to saidbrake cylinder, feeler means mounted in a feeler box on each side of thecar body adjacent said truck for indicating vertical travel of thebolster with respect to said truck side frames, each of said feelermeans comprising a feeler tube containing a stiff spring, said tubehaving an end member extending outwardly, said end member being mountedadjacent the truck side frame for movement proportional to the weight ofsaid railway car, a load compensating cylinder assembly connected tosaid brake cylinder pipe, said load compensating cylinder assemblycomprising a cylinder, a piston-mounted in said cylinder, a T-bar havingone end mounted on said piston and a pawl pivotally mounted on the otherend thereof, said cylinder having an end wall, areturn spring interposedbetween said end wall and said piston, a pawl housing carried by saidend wall, said housing having an opening in the end adjacent said pistonfor the passage of said T-bar, said housing having lower guide means forguiding the movement of said T- bar, a rack mounted on said housing forreceiving said pawl, a ratio lever, a pawl bar connecting said pawl tosaid ratio lever, a pawl spring connected to said ratio lever for urgingsaid pawl out of engagement with said rack, a sheathed cable having oneend attached to said ratio lever for urging said pawl into engagementwith the rack, an equalizer bar mounted in one of said feeler boxes, theother end of said sheathed cable being attached to said equalizer bar, afirst feeler lever connected to said equalizer bar in said one feelerbox, one of said feeler tubes being connected to said first feelerlever, a second feeler lever mounted in the other of said feeler boxes,the other of said feeler tubes being connected-to said second feelerlever, and a rod connecting said second feeler lever to said equalizerbar.

1. A braking mechanism for a railway car having a truck including sideframes, pairs of wheels, a truck bolster resting on bolster springscontained in each truck side frame and a car body carried by said truckbolster, said mechanism comprising a brake pipe, and an air brakecontrol valve connected to said brake pipe, an auxiliary reservoirconnected to said control valve and an emergency reservoir connected tosaid control valve, a brake cylinder, a brake cylinder pipe connectingsaid air brake control valve to said brake cylinder, feeler meansmounted in a feeler box on each side of the car body adjacent said truckfor indicating vertical travel of the bolster with respect to said truckside frames, a load compensating cylinder assembly connected to saidbrake cylinder pipe, said assembly comprising a cylinder, a pistonmounted in said cylinder, a T-bar having one end mounted on said piston,pawl and rack means operatively connected to said T-bar, equalizer meansmounted in one of said feeler boxes for receiving vertical movementindications from each of said feeler means and sending a correspondingindication to said pawl means.
 2. A braking mechanism according to claim1 wherein each of said feeler means comprises a feeler tube containing astiff spring, said tube having an end member extending outwardly, saidend member being mounted adjacent the truck side frame for movementproportional to the weight of said railway car.
 3. A braking mechanismaccording to claim 2 wherein said equalizer means comprises an equalizerbar mounted in one of said feeler boxes, linkage means connected to theouter ends of said equalizer bar to said feeler tubes, means connectingthe mid-portion of said equalizer bar to the pawl in the loadcompensating cylinder assembly.
 4. A braking mechanism according toclaim 1 wherein said feeler means and said equalizer means comprise anequaLizer bar mounted in said one of the feeler boxes, means operativelyconnecting said equalizer bar to said pawl and rack means, a firstfeeler lever connected to said equalizer bar, a member extendingoutwardly of said feeler box adjacent one of the truck side frames formovement proportional to the weight of said railway car, meansconnecting said member to said first feeler lever, a second feeler levermounted in the other of said feeler boxes, a rod connecting said secondfeeler lever to said equalizer bar, a second member extending outwardlyof said other feeler box adjacent the other of the truck side frames formovement proportional to the weight of said railway car, and meansconnecting said second member to said second feeler lever.
 5. A brakingmechanism according to claim 1 wherein said load compensating cylinderassembly comprises a pawl pivotally mounted on said T-bar, said cylinderhaving an end wall, a return spring interposed between said end wall andsaid piston, a housing carried by said end wall, said housing having arack mounted thereon for receiving said pawl, a ratio lever, a pawl barconnecting said pawl to said ratio lever, a sheathed cable having oneend attached to said ratio lever for urging said pawl into engagementwith said rack, the other end of said cable being attached to saidequalizer means, a pawl spring connected to said ratio lever for urgingsaid pawl out of engagement with said rack.
 6. A braking mechanismaccording to claim 5 wherein said compensating cylinder assembly furthercomprises an opening in the end adjacent said piston for the passage ofsaid T-bar, and lower guide means in said housing for guiding themovement of said T-bar.
 7. A braking mechanism according to claim 1wherein said equalizer means comprises an equalizer bar, and said loadcompensating cylinder assembly comprises ratio lever means connected tosaid pawl and rack means, cable means connecting said equalizer bar withsaid ratio lever means, and said feeler means being connected to saidequalizer bar.
 8. A braking mechanism for a railway car having a truckincluding side frames, pairs of wheels, a truck bolster resting onbolster springs contained in each truck side frame and a car bodycarried by said truck bolster, said mechanism comprising a brake pipe,an air brake control valve connected to said brake pipe, an auxiliaryreservoir connected to said control valve, an emergency reservoirconnected to said control valve, a brake cylinder, a brake cylinder pipeconnecting said air brake control valve to said brake cylinder, feelermeans mounted in a feeler box on each side of the car body adjacent saidtruck for indicating vertical travel of the bolster with respect to saidtruck side frames, each of said feeler means comprising a feeler tubecontaining a stiff spring, said tube having an end member extendingoutwardly, said end member being mounted adjacent the truck side framefor movement proportional to the weight of said railway car, a loadcompensating cylinder assembly connected to said brake cylinder pipe,said load compensating cylinder assembly comprising a cylinder, a pistonmounted in said cylinder, a T-bar having one end mounted on said pistonand a pawl pivotally mounted on the other end thereof, said cylinderhaving an end wall, a return spring interposed between said end wall andsaid piston, a pawl housing carried by said end wall, said housinghaving an opening in the end adjacent said piston for the passage ofsaid T-bar, said housing having lower guide means for guiding themovement of said T-bar, a rack mounted on said housing for receivingsaid pawl, a ratio lever, a pawl bar connecting said pawl to said ratiolever, a pawl spring connected to said ratio lever for urging said pawlout of engagement with said rack, a sheathed cable having one endattached to said ratio lever for urging said pawl into engagement withthe rack, an equalizer bar mounted in one of said feeler boxes, theother end of said sheathed cAble being attached to said equalizer bar, afirst feeler lever connected to said equalizer bar in said one feelerbox, one of said feeler tubes being connected to said first feelerlever, a second feeler lever mounted in the other of said feeler boxes,the other of said feeler tubes being connected to said second feelerlever, and a rod connecting said second feeler lever to said equalizerbar.